I started this piece in Medium by Adobe using the Terraform Studios ruins stamp pack. Scroll down to see this stage.
Then I used Blender, a bit of Marvelous designer and Photoshop to finish it. Full process on my youtube channel (or below hehehe)

Edit: I was interviewed by Adobe people in this article where we discussed how I created this piece. If you are curious check it out ;) Here is the link: https://magazine.substance3d.com/bringing-a-3d-vr-workflow-to-a-2d-scene/